This contract is part of an IDIQ multiple award pool which provides a resource for conducting nonclinical pharmacology, pharmacokinetic, and metabolism studies with candidate therapeutic agents selected for development by the Division of Cancer Treatment, NCI. Candidate therapies selected for study under this contract arise from peer-reviewed applications submitted to NCI by academic investigators, pharmaceutical companies, or others. Work carried out under the contract includes: (1) development of analytical methods to quantify the levels of test agents in biological matrices; (2) plasma stability and protein binding studies; (3) pharmacokinetic characterization following administration by various routes and schedules; (4) quantification and identification of metabolites generated; and (5) assessment of pharmacodynamic effects in tumor or surrogate tissues and correlation of these effects with levels of agent and/or total exposures. The characterizations obtained from these pharmacokinetic investigations are used in the prioritization and selection of agents for further development; in the design of preclinical efficacy and toxicology studies and in regulatory submissions in support of clinical trials of selected agents.